Insert data in embeded document MongoDB

There are situations where you need to enter data in the embeded document in MongoDB in that case the following information might come in handy.

$push

The $push adds specified value to an array.

$push operator can be used as follows:

{$push:{<field1>:<value1>,<value2>,..}}

When specifiying   <field> attribute in an embeded document or in an array use dot notation

Properties

If the value is an array,$push operator appends the whole array as a single element.To add each element of value seperately use $each

Modifiers

You can use the $push operator with the following modifiers:

Modifiers                        Description

$each                               Adds multiple values to the array fields.

$slice                              Restricts the number of array elements,requires the use of $each modifier.

$sort                              Orders the elements of the array,requires the use of $each modifier.

$position                      Specifies the location in the array where the new element are to be inserted,requires the use of $each modifier

When using the above modifiers as well the $push is wriiten as follows:

{$push:{<field1>:{<modifier1>:<value1>,<value2>,..},}}

The processing of $push operation happens in the following order when used with modifiers:

1)Update array to add elements in the correct position

2)Apply sort ,if specified

3)Sice the array,if specified

4)Store the array

Examples for various situations:

1)Append values to an array:

The following array appends 90 to the scores array

db.students.update({_id:1},{$push:{scores:90}})

2)Append multiple values to an array

Use $push with the $each modifier to append multiple values to the array field

The following example appends [90,92,85] to the scores array for the document where the name field equals rahul

db.students.update({name:"rahul"},{$push:{scores{$each:[90,92,85]}}})

3)$push operation with multiple modifiers

A collection students has the following document:

{
   "_id" : 5,
   "quiz" : [
      { "wk": 1, "score" : 10 },
      { "wk": 2, "score" : 8 },
      { "wk": 3, "score" : 5 },
      { "wk": 4, "score" : 6 }
   ]
}
The following $push operation uses:

the $each modifier to add multiple documents to the quiz array,
the $sort modifier to sort all the elements of the modified quiz array by the score field in descending order, and
the $slice modifier to keep only the first two sorted elements of the quizzes array.
db.students.update(
   { _id: 5 },
   {
     $push: {
       quiz: {
          $each: [ { wk: 5, score: 8 }, { wk: 6, score: 7 }, { wk: 7, score: 6 } ],
          $sort: { score: -1 },
          $slice: 2
       }
     }
   }
)
The result of the operation is keep only the two highest scoring quizzes:

{
  "_id" : 5,
  "quiz" : [
     { "wk" : 1, "score" : 10 },
     { "wk" : 2, "score" : 8 },
     { "wk" : 5, "score" : 8 }
  ]
}

4)pushing data to a particular location in the array  

Combination of $push ,$each and $postion operator can be used to insert data at a particular location in the array

For example:

db.students.update({name:rahul},{$push:{scores:{$each:[90,92,85],$postion:1}}})

This command will insert data [90,92,85] at the 1st postion in the scores array

Hope that the information was helpful,

THANKS